Domo began as a station mascot in Japan and travelled outward in a way mascots rarely do: a squared-off brown figure with an open mouth and no other expression, which made it endlessly reusable. The design is the reason. A character with one fixed face takes its mood entirely from the context it is placed in, so it can be menacing, cheerful or blank without being redrawn.

That is also why it spread through image boards rather than through licensing. The joke required nothing to be learned: place the figure somewhere unlikely and the caption writes itself. Mascot characters with more detail could not be borrowed as freely. This entry is kept as an archive record of one of those borrowings; the original author is not known.